Electrical winding



Feb. 19, 1957 sc w s 2,782,283

ELECTRICAL WINDING Filed May 16, 1955 INVENTOR.

United fitates Patent ELECTRICAL WINDING Donald 0. Schwennesen, Skokie,IlL, assignor to Essex Wire Corporation Application May 16, 1955, SerialNo. 508,558

3 Claims. (Cl. 200113) This invention relates to electrical transformersand in particular to the use of a fuse wire with transformers.

It is a generally accepted requirement of power transformers forhousehold appliances that they contain an integral circuit breaker. Inthe event that the transformer overheats or draws excessive current, itis expected that the circuit breaker Will open the primary side. Theusual circuit breaker so employed is a fuse wire connected in theprimary usually at or associated with the connection of the lead wiresand in temperature sensing relation with the transformer winding.

One difficulty with such a connection has been the occurring of nuisancecircuit breaking due to mechanical stress applied to the fuse wire. Inaddition, previous connecting systems available have been bulky, andinefficient due to the extra wiring required.

It is an object of this invention to provide a preassembled wiringlead-in assembly which contains a fuse wire and which is structurallycompact and durable as well as economical.

In the drawings:

Fig. 1 is a perspective view of a complete win-ding illustrating theapplication of pie-assembly.

Fig. 2 is a plan view of the pre-assembly.

Fig. 3 is a bottom view of the pre-assembly.

Referring to Fig. 1, the pro-assembly is illustrated with four lead-inwires, however, any number may be employed to accommodate the number oftaps on the transformer coil. Quite commonly power transformers forradio and television use have a considerable number of transformer tapsto provide different voltages from the same transformer.

In the case of Fig. 1, wires and 11 are secondary leads and wires 12 and13 are primary leads. All leads are stripped to facilitate splicing. Thetransformer coil is indicated generally at 14 and is wound in theconventional manner with a layer of insulating material between theconvolutions of magnet wire. The taps are brought out in a manner thatis well understood in the art and are extended upwardly as at 15, 16,17, and 18, to engage the lead-in wires.

The base piece 19 is an insulating member separating the pre-assembly 21from the coil proper. The edge piece serves as a support piece for thetake-outs to prevent any cutting action by the take-out wires againstthe edge of the coil.

The pie-assembly is indicated in Figs. 2 and 3. The fuse wireconstruction is associated with lead-in wire 13. Leads 10, 11, and 12,or, as indicated previously any number of wires corresponding to thetaps on the coil, are connected directly to the take-out leads.

The panel 22 is constructed of insulating paper board or the like andhas a series of apertures 23 and staples 24 for securing the individualleads. The insulated leads 10, 11, and 12 are individually threadedthrough the apertures 23 and secured by staples 24. The stripped ends ofleads 10, 11, and 12 are spliced to take-out leads 15, 16, and 17 andfolded back on the panel 22 or deposed in any suitable manner which willavoid shorting contact between adjacent leads. Lead 13 is similarlythreaded through an aperture 23 and stapled. The lead 13 is not,however, connected to a coil tap. Instead it is spliced to jumper 25.The jumper wires 25 and 26 parallel lead 13 and are firmly anchored inplace by the construction at features employed. The jumpers aresimilarly threaded through apertures 23 and 27 so that both free ends 28and 22 are on the underside of the panel 22. The free ends of thejumpers are sufficiently long to permit crimping over the panel edge asat 3% and 31 and the wires are seized by stapling as at 24. The otherend of the wire 26 .is spliced to the coil take-out lead 13.

Fig. 3 shows the bottom view of the pie-assembly and the exposed freeends 23 and 2% of the wires 25 and 26. The fuse wire 32 is solderedacross the wire jumpers to complete an electrical circuit through lead13, jumper 25, fuse 32, jumper 26, and coil tap 18. Due to the seriesconnection of the fuse wire in the primary circuit, abnormal transformertemperature or excessive primary circuit voltage will cause the fuse toopen the primary circuit.

It is to be particularly noted that the construction of the pre-assemblyminimizes the mechanical stress on the soft fuse wire due to stressesapplied to any of the preas'sembly lead wires.

Having thus described my invention, 1 claim:

l. A pre-assembly of connection leads for multitap electricaltransformers consisting of a plurality of insulated wires including twoprimary leads all with stripped ends, an insulating panel having anumber of apertures at least equal to the number of insulating leads,said insulating wires lying upon the outermost surface of said panel andstapled thereto, said stripped ends threaded through said apertures forconnection to transformer take-out leads, two jumper wires positionedadjacently parallel one of said primary leads, one jumper spliced tosaid primary lead, the other jtunper fused to the transformer primarytake-out tap, and a fuse wire joining the remote ends of said jumperwires.

2. A pre-assembly of connection leads for multitap electricaltransformers consisting of a plurality of insulated wires including twoprimary leads all with stripped ends, an insulating panel having anumber of apertures at least equal to the number of insulating leads,said insulating wires lying upon the outermost surface of said panel andstapled thereto, said stripped ends threaded through said apertures, twojumper wires positioned adjacently parallel one of said primary leads,additional panel apertures through which both ends of the jumper Wiresare threaded, one jumper spliced to said primary lead, the remainingjumper spliced to the transformer primary takeout tap, and a fuse wirejoining the remote ends of said jumper wires on the undermost side ofsaid panel.

3. A pre-as'sembly of connection leads for electrical coil windingsconsisting of a plurality of insulated lead wires all with strippedends, an insulating panel having a number of apertures at least equal tothe number of insulated lead wires, said insulated lead wires lying uponsaid panel and staple-d thereto, said stripped ends threaded throughsaid apertures for connection to coil take-out lead wires, a fuse wireelectrically connected between one of said insulated lead wires and acoil take-out lead wire, and the other insulated lead wires electricallyconnected to their corresponding coil take-out lead Wires.

References Cited in the file of this patent UNITED STATES PATENTS

